The present invention relates to an apparatus for use in the field of packaging machines for foods and the like for determining the rate of discharge from a nozzle for spraying an aqueous solution of hydrogen peroxide, for example, to sterilize containers.
The rate of discharge from such a spray nozzle is usually determined from the rate of flow through a pipe for supplying a pressurized aqueous solution of hydrogen peroxide by measuring the flow rate with a flowmeter of the differential pressure type or electromagnetic flowmeter. However, since the amount of the solution flowing through the supply pipe is very small, it has been impossible to accurately measure the very small rate with any flowmeter and therefore to accurately determine the discharge rate. The reason is that the aqueous hydrogen peroxide solution releases oxygen when decomposed by exposure to heat, contact with impurities or the flow of itself, permitting the resulting oxygen to flow along with the solution.
Further since the solution is highly corrosive, the flowmeter must be ingeniously protected against corrosion. This encounters difficulties and requires an increased cost.